Railway-traffic-controlling apparatus



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UNITED STATESPATENT OFFICE.

HOWARD A. THOMPSON, 0F EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THEUNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORA-TION OF PENN SYLVANIA.

nAILwAY- rnurIo-conmoLmNG arrana'rus.

Application filed March 20, 1928. Serial No. 263,118.

My invention relates to railway traffic controlling apparatus, andparticularly to apparatus of the type comprising train-carried governingmeans controlled by train governing energy received from the trackrails. More particularly my present invention relates to the track'wayportion of such apparatus.

I will describe two forms of trackway apparatus embodying myinvention,and will then point out the novel features thereof in. claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing oneform of trackway apparatus embodying my invention. Fig. 2 is a diarammatic View showing a modification o a portion of the ap paratus shownin Fig. 1 and also embodying my invention.

Referring first to Fig. l, the reference characters 1 and l designatethe track rails of a railway track over which traffic moves at times inboth directions. These rails are divided by insulated joints 2 intoblocks which are made up of main track sections and reset tracksections. In the drawing I have illustrated only one block, which blockcomprises a main section, AB, a reset section A -A at one end, of themain section, and a second reset section B 'B at the other end of themain section. The first of these reset sections may be termed thewestbound reset section, and the second may be termed the eastboundreset section. Each reset section is comparatively short, and may, forexample, be 100 feet to 200 feet in length. is a westbound signal S andan eastbound signal S Located adjacent the .point B 1s a westboundsignal S and an eastbound signal S". Each signal is provided with asignal relay or line relay which is designated by the referencecharacter H with the same exponent as that applied to the associatedsignal.

The signals are controlled in accordance with what is known in therailway signaling art as absolute permissive block signaling. That is tosay, when an eastbound train leaves the tirstpassing siding to the westof point A it opens relays H and H so that si nals S and S both changeto the stop in imtion. When the train passes signal S this signal, ofcourse, assumes the stop indication, and when the'train passes signal S,thelatter signal also assumes the stop indication. :When a westboundtrain leaves the next passing s ding to the east of point B, itdeenergizes relays H and H*, but relay H remains energized until thetrain passes signal S and relay H remains energized until the trainpasses signal S". The apparatus for controlling relays H in the mannerspecified, is omitted from the drawing, because the control of theserelays has nothing to do with my present invention.

The reset section A -A is constantly supplied with alternating currentfrom a transformer T the primary 3 of which is connected with atransmission line L which in turn is connected with a generator G. Thecurrent thus supplied to reset section A -A 1s converted intounidirectional current by a rectifier R and this unidirectional currentis supplied to the rails of the main sect1on A-'B' from which it istaken through a rectifier R and supplied to the rails of section B-B andso to a track relay C for the block between points A and B The cir-'cuit for the secondary of transformer T is from the left-hand terminalof this secondary, through wire 5, rail 1-of reset section.

A A, wire 6, reactance 7, rectifier R wires 8 and 9, rail 1 of the mainsection A-B, wire 54;, rectifier R wire 10, rail 1 of reset section13-13 wires 11 and 12, winding of track relay C, wires 13 and 14, rail 1of reset section B-B wire 15, reactance l6, rectifier R reactance 17,rail 1 of main section AB, wire '18, reactance 19, rectifier R wire 20,rail 1 of section A1'A, wire 21, and reactance 22 to the right-handterminal of the secondary 4 of transformer T It will be seen, therefore,that the terminals of secondary 4 are connected with one end of one railand the other end of the other rail of section A -A, whereas the inputterminals of rectifier R are connected with the free ends respectivelyof the two rails of this section. The output terminals of rectifier Rare connected with the two rails of section A-B respectively at the westend of this section.

The input terminals of rectifier R are connected with the two railsrespectively of section AB adjacent the east end of this sec- 7 tion,whereas the output terminals of rectifier R are connected with one endof one rail and the other. end of the other rail of section B-B. Trackrelay C is connected with the free ends respectively of the rails ofsection B-B It follows that alternating current always flows in one railof reset section A A even when this section is occupied by a train, andthat track relay C, which is of the direct current type, receivesunidirectional current when there is no-train between signals S and SWhen, a westbound train is approaching signal S relay H is, of course,de-energized, whereupon alternating train governing current is suppliedto the rails of section A-B by a transformer T if relay H is energized.The circuit for the primary 55 of this transformer is from the lowerline wire L, through wires 23 and 24, back contact 25 of relay H frontcontact 26 of relay H wire 27, primary 55, and \fii'es 2 8 and 29 to theupper line wire The left-hand terminal of secondary 56 of transformer Tis connected with rail 1 by wires 30 and 18, whereas the right-handterminal of this secondary is connected with rail 1 through a resistance31 and wires 32 and 9.

When either relay H or H is de-energized, alternating train governingcurrent is supplied to the rimary 57 of a transformer T When relay $1 isde-energized, the primary circuit for transformer T is from the lowerline wire L, through wire 33, back contact 42 of relay H wires 43 and36, primary 57 and wire 37 to the upper line wire L. When relay H isde-energized, the circuit is the sameexcept that it includes wire 34 andback contact 35 of relay H The left-hand terminal of secondary 58 oftransformer T is connected with rail 1" at the left-hand end of sectionBB, through wires 38 and 11; the righthand terminal of secondary 58 isconnected with rail 1 at the right-hand end of section B-B ,'through aresistance 40 and wires 39 and 14.

The reference character T designates a transformer for supplying traingoverning current to the main section AB while an eastbound train isproceeding through this section. The primary circuit for transformer Tis closed when and only when track relay C is de-energized and relay His energized, the circuit then being from secondary 58 of transformer Tthrough wires 38 and 11, track rail 1", wires 10 and 44, primary oftransformer T wire46, back contact 47 of relay C, wire 48, front contact49 of relay H wire 50, resistance 51, wire 15, rail 1, wires 14; and 39and resistance 40 to secondary 58 of transformer T The secondary 52 oftransformer T is connected across the rails of section A.-B, aresistance 53 being interposed erning current to at least one of thetrack rails to prevent a stop indication of any suitable kind, such asan automatic application of the brakes. If the supply of such current isdiscontinued, a stop indication will result unless the engineman takesproper action to acknowledge the chan e in traffic conditions. If hedoes acknowledge, the train may proceed without incurring a stopindication, but if alternating current is again supplied to the railsoccupied by the train and this current is subsequently discontinued, theengineman must again acknowledge to prevent a stop indication. One formof train-carried governing means suitable for co-operationwith thetrackway apparatus herein disclosed is shown and described in UnitedStates Letters Patent, Reissue No. 16,502, granted on December 7, 1926,to Ronald A. McCann, for railway traiiic controlling apparatus. Inapparatus of the type described in that patent, the train-carriedgoverning means is controlled by alternating current in the track railsthrough the medium of an inductive receiver mounted on the train inadvance of the forward axle, so that it is necessary for the alternatingtrain governing current to flow through at least one track rail inadvance of the train in order to prevent an automatic application of thebrakes.

The operation of the apparatus shown in Fig. 1, is as follows: I willfirst assume that an eastbound train passes along the track and thattrafiic conditions to the east of point B are clear, so that relay H isenergized. As the train leaves the first passing siding to the west ofsignal S, relays H and H both become de-en'ergized. Relay H has noeffeet on the parts of the apparatus shown in the drawing, but theopening of relay H causes train governing current to be supplied totransformerT and so to: the rails of resetsection BB As the train entersreset section A A it receives alternating current through rail 1 and soa clear indication is given aboard the train. Alternating current is nowshunted away from rectifier R however, so that track relay C opens.Relay H and track relay C both being open, and relay H being energized,train governing current is supplied from transformer '1 to transformer Tand so to the rails of section AB, with the result that when the trainenters this section it will receive train governing current from both ofthe track rails and so the proceed indication aboard the train will becontinued. When the train enters the reset section 13-48 it will receivetrain governing current from rail 1 of this section due to the fact thatrelay H is still open, and so the proceed indication aboard the trainwill be continued.

Assuming now that a westbound train passes along the track, relays H andH will be opened as soon as such train leaves the first passing sidingto'the east of point B. As

suming that traflic conditions to the west of signal S are clear, relay1-1 will be energized, and since relay H is open, alternating traingoverning current will be supplied to the primary of transformer T andso to the rails of section AB. Alternating current is also supplied tothe primary of transformer T3, because relay His open, and so thiscurrent is supplied to the rails of reset section 13-13 The train willtherefore receive a proceed indication "throughout the entire blockbet-ween signals S and S Reverting now to the movement of an eastboundtrain, I will assume that as this train approaches signal S relay H isopen, so that signal S indicates stop and signal S indicates caution.The eastbound train will then receive a proceed indication until itpasses point A, but upon entering section A-B it will receive a stopindication, because the primary circuit for transformer T is now open atfront contact 49 of relay H". The engineer must therefore acknowledgethe caution indication of signal S in order to' avoid an automaticapplication of the brakes at point A. Upon entering reset section B-Bthe train Will receive alternating current from rail 1, due to the factthat the primary circuit for transformer T is closed at both contacts 42and 35 of relays H and H. Upon passing signal S the supply ofalternating current will cease, because of the occupied condition of thetrack to the east of this signal, with the result that the engineermustagain acknowledge in order to avoid an automatic application of thebrakes. Assuming now that the main section A-B is occupied, and that aneastbound train asses over the track. Upon passing signal 2 the trainwill receive alternating current from rail 1 of section A A-, but thesupply of alternating current will cease as soon as the train enterssection AB, with the result that the engineer must acknowledge in orderto avoid an automatic application of the brakes.

Assuming now that signal S is at stop and that a westbound train passessignal S the supply of alternating current will be discontinued at pointB, because the primary circuit for transformer T is open at contact 26of relay Consequently, the engineer must acknowledge the cautionindication given by signal S in order to avoid a brake application. Uponentering reset section A A, the apparatus on the train will be reset,because of the fact that the train re ceives alternating current fromrail 1, but the supply of alternating current will cease upon passingsignal S and so the engineer must acknowledge the stop indication ofthis signal in order to avoid a brake application.

It will be observed that alternating current is fed to the reset sectionA A and 1s then converted into unidirectional current to any reason, sothat thisse'ction would be ineffective to reset the locomotiveequipment,

the defect will cause the track relay C to become de-energized, with theresult' that signal "S willassume the stop indication and thenextwestbound signal in the rear will, of course, indicate caution.Similarly, should anything occur to prevent the supply of alter natingcurrent from transformer T to the rails ,of reset section BB the supplyof train governing current to transformer T would, ncessarily, cease,with the result that an eastbound train entering section AB wouldreceive a stop indication.

Reactance 22 is interposed between transformer T and the track rail 1 tolimit the amount of alternating current flowing from the secondary ofthis transformer when a train stands in section A A. Reaetance 7 is usedto limit the amount of alternating current supplied through rectifier Rto the remaining portion of the track circuit, so that when the trackcircuit is not occupied transformer T will furnish only the amount ofcurrent necessary to operate track relay C. Reactance 19 is inserted inthe output circuit of rectifier R to smooth out the rectifiedcurrentsupp'lied to the rails of section A-B and to prevent thesecondary 56 of transformer T from being short circuited by rectifier RResistance 31 is included in the secondary circuit for transformer T forthe usual purpose of limiting the amount of current supplied by thistransformer to the track rails when a train occupies section AB. Thepurpose of resistance 53 is the same as that of resistance 31. Thepurpose of reactance 17 is the same as that of reactance 19, and thepurpose of reactance 16 is the same as that of reactance 7. The purposeof resistance 51 is to limit the amount of current supplied to'theprimary of transformer T when a train occupies section I\B, and also toprevent shunting rails 1 and 1 of section B-B at times. Suppose aneastbound train enters section AB with signal H at clear and then backsout of the section or leaves by a siding switch. Relay C would not beenergized due to shunt 15--5t)-48-4G-44-10. Resistance 40 is used tolimit the output current of trans former T" when a train occupiessection Referring now to Fig. 2, I have herein llr lustrated amodification of the apparatus shown at location A in Fig. 1. In Fig. 2the output circuit for rectifier R passes through the secondary 56 oftransformer T so that one output terminal of the rectifier is connectedwith rail 1* through wire 59, and the other output terminal is connectedwith rail 1 through secondary 56 and wire 60. Rectifier R transforms thealternating current into unidirectional current as before, but thisrectifier also functions as a single wave rectifier for the traingoverning current supplied by transformer T It follows that the traingoverning current supplied to section AB from this transformer will behalf waves only, so that the amplitude of this current must be increasedto compensate for the fact that one-half of each wave is eliminated. Theadvantage of the apparatus shown in Fig. 2, is that a failure of thesecondary circuit of transformer T will result in failure to energizetrack relay C, with the result that signaLS will indicate stop, and thewestbound signal next in the rear will indicate caution.

Although I have herein shown and described only two forms of apparatusembodying my invention, it is understood that various changes andmodifications may bemade therein within the scope of the appended claimswithout departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is z,

1. In combination, a stretch of railway track divided into a mainsection and a relatively short reset section at each end of the mainsection, a source of alternating current having its terminals connectedwith one end of one rail and the other end of the other railrespectively of the first reset section, a rectifier having its inputterminals connected respectively with the free ends of the rails of saidfirst reset section, the output terminals of said rectifier beingconnected with the rails of said main section, a second rectifierterminals connected with one end of one rail and the other end of theother rail of the second reset section, and a direct current track relayhaving its terminals connected with the free ends respectively of therails of said second reset section and operated by the rectified currentsupplied from said alternating current source.

2. In combination, a stretch of railway track divided into a mainsection and a relatively short reset section at each end of the mainsection, a source of alternating current having its terminals connectedwith one end of one rail and the other end of the other railrespectively of the first reset section, a rectifier having its inputterminals connected respectively with the free ends of the rails of saidfirst reset section, the output terminals of said rectifier beingconnected with the rails of said main section, a second rectifier havingits input terminals connected with the rails of said main section andits output terminals connected with one end of one rail and the otherend of the other rail of the second reset section, and a direct currenttrack relay having its terminals connected having its terminalsconnected with one end of one rail and the other end of the other railrespectively of the first reset section, a rectifier having its inputterminals connected respectively with the free ends of the rails of saidfirst reset section, the output terminals of said rectifier beingconnected with the rails of said main section, a second rectifier ha ingits input terminals connected with the ails of said main section and itsoutput terminals connected with one end'of one rail and the other end ofthe other rail of the second reset section, and a direct current trac'krelay having its terminals connected with the free ends respectively ofthe rails of said second reset section and operated by the rectifiedcurrent supplied from said alternating current source, and meansoperating when a train occupies or is approaching said second resetsection to connect the terminals of a second source of alternatingcurrent with the said free ends respectively of said second resetsection.

4. In combination, a stretch of railway track divided into a mainsection and a relatively short reset section at each end of the mainsection, a source of. alternating current having its terminals connectedwith one end of one rail and the other end of the other railrespectively of the first reset section, a rectifier having its inputterminals connected respectively with the free ends of the rails of saidfirst reset section, the output terminals of said rectifier beingconnected with the rails of said main section, a second rectifier havingits input terminals connected with the rails of said main section andits output terminals connected with one endof one rail and the other endof the other rail of the second reset section, and a direct currenttrack relay having its terminals connected with the free endsrespectively of the rails ofsaid second reset section and operated bythe rectified current supplied from said alternating current source,means operating when a train occupies or is approaching said secondreset section to connect the terminals of a second source of alternatingcurrent with the said free ends respectively of said second resetsection, means operating when said track relay is open and trafficconditions beyond said secnd reset sections are safe to supplyalternating current from the first mentioned ends of said second resetsection to the rails-of said main section, and means controlled bytraffic conditions beyond said first reset section for supplyingalternating train governing current to the rails of said main sectionwhen the main section is occupied. I

5. In combination, a stretch of railway track divided into a mainsection and a relatively short reset section, a source of alternatingcurrent having its terminals connected with one end of one rail and theother end of the other rail respectively of said reset section, arectifier having its input terminals connected respectively with thefree ends of I the rails of said reset section and having its outputterminals connected with the rails of said main section, and a directcurrent track relay receiving. current from the rails'of said mainsection and responsive to the unidirectional current furnished fromsaid'source by said rectifier.

-6. In combination, a stretch of railway track divided into amainsection and arelatively short reset section, a source of alternatingcurrent haying its terminals connectof the other .rail respectively ofsaid reset section, a rectifier having its input terminals connectedrespectively with the free ends of the rails of said reset section andhaving its output terminals connected with the rails of said mainsection, a direct current track relay receiving current from the railsof said main section and responsive to the unidirectional currentfurnished from said source by said rectifier, and means controlled bytrafiic conditions for supplying alternating train governing current tothe rails of said main section.

7. In combination, a stretch of railway track divided into a mainsection and a relatively short reset section, 'a source of alternatingcurrent connected With the rails of said reset section, arectifierhaving its input terminals connected with the rails of said resetsection and its output terminalsconnected with the rails of said mainsection, and a direct current track relay receiving current from therails of said main section and re.- sponsive to the unidirectionalcurrent furnished from said source by said rectifier.

In testimony whereof I aflix my signature.

' HOWARD A. THOMPSON.

